Nb-doped NiFe LDH nanosheet with superhydrophilicity and superaerophobicity surface for solar cell-driven electrocatalytic water splitting

The construction of transition-metal-based bifunctional electrocatalysts with high activity and stability remains a challenge for efficient water splitting. In this work, we designed an Nb-doped NiFe LDH nanosheet array grown on nickel foam (NF), which shows superior OER and HER activity with low overpotentials of 277 mV and 331 mV to achieve the current density of 100 mA cm–2, respectively. As is revealed by in-situ Raman spectra, the outstanding bifunctional performance originated from the regulated electron structure brought by Nb dopants. In addition, the unique “superhydrophilicity and superaerophobicity” surface feature of the NiFeNb LDH improves the diffusion of electrolytes and promotes the release of the formed gas bubbles thus further facilitating the catalytic process. Attributed to the high OER and HER activity, the NiFeNb-0.25/NF could be used as a bifunctional electrode to assemble a solar-driven electrocatalytic water-splitting configuration, which reveals an impressive solar-to-hydrogen (STH) efficiency of 15.56%. This work opens up a way for the development of efficient dual-function electrocatalysts in doping engineering.